Earth boring auger and head therefor



March 12, 1957 J, FREEMAN 2,784,944

EARTH BORING AUGER AND HEAD THEREFOR Filed July 10, 1953 fa ene J. flee/nan This inventionrelates generally to earth boring tools and is directed particularly toimprovements in tools of this character designed 'for form'ing post holes or other holes in the earth.

The present invention is an improvement upon my Post Hole Digger AttachmentforrElectric'Drills forming the subject matter of application Serial No. 310,21l,-filed September 18, 1952, tand nowabandonedand a principal object of the present invention'is toprovide a novel lead member for such digger whereby the-digger or anger is readily started intothe ground withoutnecessity of having to apply pressure thereto in addition to the pressure which would be applied by the weight of the tool itself.

Another object .of'the inven'tion is to .provide in an earth auger ordigger attachment for electric and other types of rotary drills, a lead member which is formed in a novel manner and is "readily'attached to'the blades of the earthdrilling'toolor'auger.

Other objects and advantages of the inventionwill be come apparent as the 'descri'pti-on'of the samejproceeds and the invention will bebestunderstood from a consideration of'the'followi'ng detailed description taken in connection with the accompanying'drawings forming a part of the specification, with the understanding, however, that the invention is not to be limited to the exact details of construction shown and described since obvious modifications will occur to a person skilled in the art.

In the drawing:

Figure l is a view in elevation of an earth digger or auger constructed in accordance with the present invention and showing the starter member attached thereto.

Figure 2 is a detail view on an enlarged scale showing the shovel members in longitudinal section, together with sectioned portions of the connecting yoke between the shovels.

Figure 3 is a bottom plan view of the invention applied to the earth auger.

Figure 4 is a plan view of the blank from which the starter member is formed.

Figure 5 is a detail sectional view of the head member employed for connecting the tool carrying shaft with the chuck of a rotary power tool.

Fig. 6 is a fragmentary plan view of the inner ends of the upper pair of blades showing how they are notched.

Referring now more particularly to the drawing the numeral 10 generally designates a conventionally illustrated chuck such as forms a part of any standard electric drill with which the present tool is designed for attachment.

The earth auger or post hole digging tool comprises a head portion which is generally designated 12 and with which is connected one end of a shaft 14.

The opposite end of the shaft 14 is connected in a suitable manner with the drill chuck 10. The preferred means of connecting the tool shaft with the chuck is here shown as comprising a tubular head 16 of hexagonal '1 nited States Patent 0 coupling bar 26, the oppositeen'd of the of the shaft 14 longitudinally with respect to the shaft 14 from or beyond the lower end thereof.

its concave face against the outer side of an .plate 34, as shown, :to which it is securely fastened by rivets 38, or in any other suitablemanner.

'the slot, are and 42.

2,784,944 Patented Mar. 12, 1957 end portion 20 of the shaft. The opposite end of the head '16 has a threaded 'axial bore 22 in which is threadably engaged the threaded stem portion 24 of a hexagonal bar being secured in the power toolchuck in the manner illustrated.

As previously stated, the means here shown for connecting the auger with "the power tool is :preferred but it is to be understood that the invention is not limited to this type ofcoupling.

The auger head comprises an arcuate yoke 23 which is provided midway of its ends-with an internally threaded socket St; in which the threaded lower end portion 32 is engaged as shown in Figure 2.

The two ends of the yoke '28 'are provided with the longitudinally extending terminal attaching plates 34, which plates are in spaced aparallel relation and extend and away The auger head alsoincludes thetwo elongate shovels 36, eachof which is transversely curved or is of arcuate cross section andeachshovel has one end positioned with attaching The lower, or digging endsof the shovels 35, are each provided with a longitudinal slot 4t) which is located upon onesideof the longitudinal center of the shovel and the two portionsof the shovel which are thus formed by bent inwardly to-provide the two blades 41 :straight radial edge 44, which is the edge forming one side of the slot 40. The inwardly directed corners of the blades 4-2, where the edges 43and .44 intersect, are cut out to form notches 45. The tip of each blade 42 is notched by making two intersecting cuts, each substantially normal to one of the edges 43 and 44 producing an angular notch with straight sides which are approximately perpendicular to each other, as shown in Fig. 6. These inner corners of the blades 42 are brought together in mutually overlapping relation so that the notches 45 fit one into the other. The blades cross each other, so that the extreme inner tip of each blade is spaced a short distance below the other blade. The back. sides of notches 45, which are parallel to edges 44, bear against each other.

In addition to the interlocking connection of the notches 45, of the blades 42, there is provided a short coupling strap 46, which extends across the overlapped notched corners of the blades and is riveted, at its ends, as indicated at 47 to the blades 42.

As is clearly shown in Figures 1 and 2, the larger and connected, blades 42 are extended inwardly toward the longitudinal center of the auger at a slightly obtuse angle to the length of the shovels of which they form a part. However, the shorter blades 41 extend inwardly and downwardly on a relatively wide are as clearly shown in Figures 1 and 2.

Each of the shorter blades 41 has a straight advancing cutting edge 48 which forms the opposite side of the slot 46 from the straight edge 44 and a trailing curved edge 49.

When the auger is rotated clockwise (counterclockwise when viewed as in Fig. 3) the cutting edges of the shorter blades 41 will work into the earth in advance. of the longer blades 42, the wide sweeping cutting edges 43 of which larger and longer blades cut away the center part of the hole being formed after the shorter blades have cut in around the axial center of the hole.

In order to facilitate the starting of the auger into the earth and also the maintenance of the auger on a straight cutting path, the ends of the shorter blades 41 are con nected by the lead member which is generally designated 50.

This lead member 50 is formed from a single elongate sheet of metal of suitable weight which is illustrated in Figure 4, and which is generally designated B. In the formation of the lead member the piece of metal or blank B is suitably tapered at one end to provide a point 51 and it is split from the center of the opposite end edge, longitudinally as indicated at 52 through the major portion of its length, the inner end of the split 52 lying on a transverse line passing approximately across the points along the longitudinal edges of the blank where the taper for the point 51 begins.

The splitting of the blank along the line 52 thus forms two elongate wings 53 and these wings are pulled apart as shown in Figures 1 and 2 so that the lead member assumes substantially a V form.

The outer ends of the wings 53 are secured against the underfaces of the short blades 41 as shown, so as to place the point 51 on the longitudinal center of the auger, and of course, directed away from the connected blades 42 or in the direction in which the auger is to travel.

From the foregoing it will be seen that by the provision of the pointed or substantially V-shaped lead member 50, the auger when placed in position on the ground and rotated, will maintain its position and start the hole exactly in the desired spot due to the centering or leading action of the lead member 50. Lead member 50 has a tapered end section 51 which is relatively thin and has a sharp point. it penetrates the ground easily because of its shape and small size, and digs a hole in advance of blades 41. Once in the ground, the leading corner at each side edge of section 51 acts as a cutting edge. As the lead member descends, these leading corners scrape away the soil to dig a hole of increasing diameter and allow the lead member to advance. Because of the taper to the sides of section 51, lead member digs both vertically and horizontally as the auger rotates. At the same time the lead member fits snugly within the bore hole it makes to resist any lateral movement of the auger as a whole, thus assisting. the operator to hold it in a selected spot and start the hole properly. Likewise the member 50 will continue to function to keep the auger in a straight path during its penetration into the earth. Thus it will be seen that in order to start the auger it is not necessary for the operator to apply any special pressure to keep the auger in starting position.

I claim:

An earth auger comprising: a yoke; a shaft secured at one end to the center of the yoke and having a longitudinal axis about which the auger is rotated; a pair of elongate shovels each secured at one end to one end of the yoke and extending away from the yoke in a direction generally parallel to said axis; a pair of radially inwardly directed blades carried by each shovel at the end thereof away from the yoke, one blade of each pair being more remote than the other from the yoke; a

strap crossing the axis of rotation and joining the inner ends of the blades of each pair nearer to the yoke; and a pointed lead member connecting the inner ends of the more remote blades of each pair, said lead member comprising a fiat, thin terminal section having a point located on the axis of rotation of the auger and two flat wing members extending in opposite directions from the fiat sides of the terminal portion, each wing member sloping upwardly and lying against the outer face of one of the more remote blades to which the wing member is secured.

References Cited in the file of this patent UNITED STATES PATENTS 116,883 Stone July 11, 1871 633,574 Densmore Sept. 26, 1899 727,322 Erzig May 5, 1903 732,859 lwan July 7, 1903 835,125 Webb Nov. 6, 1906 977,877 Jenney Dec. 6, 1910 1 1,067,417 Erzig July 15, 1913 1,504,852 Wright Aug. 12, 1924 

